C# 给pdf文件加背景图 例子源码下载

pdf加背景后的效果图：
public class ImageBackground{ public void SetBackground(string pdfFile, string destFile, Drawing.Image image) {...} public void SetBackground(string pdfFile, Stream stream, Drawing.Image image) {...} public event EventHandler<SetBackgroundProgressEventArgs> Progress; public event EventHandler<SetBackgroundErrorEventArgs> Error; public event EventHandler Finish;}